//---------------------------------------------------------------------------
//                                        RENDERING A DIGITAL ELEVATION MODEL
//                                                               FROM SCRATCH
//
//                              STEP 1: OPEN FILE AND RENDER USING COLOR RAMP
//                              STEP 2: FLIP THE IMAGE VERTICALLY
//                              STEP 3: FIND MINIMUM AND MAXIMUM
//                              STEP 4: ADD SLIDERS
//                              STEP 5: as per your imagination...
//----------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
#include <fstream.h>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
   : TForm(Owner)
{
}

//--------------------------------------------------------------------- NOTES
// data file contains 562 data items per line
// data file contains 492 lines of data
// aside from zero, the minimum elevation is 105
// the maximum elevation is 3486

//--------------------------------------------------------- DECLARE VARIABLES
int sluis[492][563];
int minElev;
int maxElev;
int elevation[3500];
int level;
int topLeft, bottomRight;
int topRight, bottomLeft;
int top, bottom;
int lastElev;
bool gray = false;

// ------------------------------------------------------ COLOR RAMP FUNCTION
int colorRamp (int range, int value) {
   if (range==0) range=1;
   if (value < 0) value = 0;            // interesting if deleted
   if (value > range) value = range;    // interesting if deleted
   int pixelDistanceAlongPath = (value*1792)/range;
   int red, green, blue;
   if (pixelDistanceAlongPath < 256) {
      red=0; green=0; blue=pixelDistanceAlongPath;
   }
   else if (pixelDistanceAlongPath < 512) {
      red=0; green=pixelDistanceAlongPath-256; blue=255;
   }
   else if (pixelDistanceAlongPath < 768) {
      red=0; green=255; blue=255-(pixelDistanceAlongPath-512);
   }
   else if (pixelDistanceAlongPath < 1024) {
      red=(pixelDistanceAlongPath-768); green=255; blue=0;
   }
   else if (pixelDistanceAlongPath < 1280) {
      red= 255; green= 255-(pixelDistanceAlongPath-1024); blue=0;
   }
   else if (pixelDistanceAlongPath < 1536) {
      red=255; green=0; blue=pixelDistanceAlongPath-1280;
   }
   else {
      red=255; green=pixelDistanceAlongPath-1536; blue=255;
   }
   if (gray) {
      int ave = (red + green + blue) / 3;
      red = ave; green = ave; blue = ave;
   }
   return (RGB(red,green,blue));
}

//-------------------------------------------------------------------- RENDER
void render (void) {
   for (int e = 0; e < 492; e++) {
      for (int s = 0; s < 563; s++) {
         Form1->Canvas->
            Pixels[e][s] = static_cast<TColor>
            (colorRamp(maxElev - minElev,
            sluis[e][s] - minElev));
      }
      Form1->ProgressBar1->Position = e;
   }
   Form1->ProgressBar1->Position = 0;
}

//----------------------------------------------------- ELEVATION STATISTICS
void elevationStatistics (void) {
   minElev = 2000;
   maxElev = 0;
   for (int e = 0; e < 492; e++) {
      for (int s = 0; s < 563; s++) {
         if (sluis[e][s] != 0) minElev = min(minElev, sluis[e][s]);
         maxElev = max(maxElev, sluis[e][s]);
         elevation[sluis[e][s]]++;
      }
   }
   Form1->EditMin->Text = minElev;
   Form1->EditMax->Text = maxElev;
   Form1->TrackBarMin->Position = minElev;
   Form1->TrackBarMax->Position = maxElev;
   Application->ProcessMessages();
   // Render elevation histogram
   for (int i = 0; i < 1500; i++) {
      Form1->PaintBox1->Canvas->MoveTo(0, (1000 - i) / 2);
      Form1->PaintBox1->Canvas->LineTo(elevation[i] / 30, (1000 - i) / 2);
   }
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 0) / 2, "0 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 100) / 2, "100 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 200) / 2, "200 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 300) / 2, "300 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 400) / 2, "400 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 500) / 2, "500 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 600) / 2, "600 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 700) / 2, "700 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 800) / 2, "800 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 900) / 2, "900 ");
   Form1->PaintBox1->Canvas->TextOut(0, (1000 - 1000) / 2, "1000 ");
}

//----------------------------------------------------------------- OPEN FILE
void openFile (void) {
   if (Form1->OpenDialog1->Execute()) {
      ifstream infile(Form1->OpenDialog1->FileName.c_str());
      for (int e = 0; e < 492; e++) {
         for (int s = 562; s >= 0; s--) {
            infile >> sluis[e][s];
         }
         Form1->ProgressBar1->Position = e;
      }
      infile.close();
   }
   Form1->ProgressBar1->Position = 0;
   elevationStatistics();
   render();
}

//--------------------------------------------------------------------- FLOOD
void flood (void) {
   Form1->ProgressBar1->Max = 1500;
   for (level = 0; level < 1500; level = level + 2) {
      for (int e = 0; e < 492; e++) {
         for (int s = 0; s < 563; s++) {
            if ((sluis[e][s] < level) && sluis[e][s] > level - 3) {
               Form1->Canvas->Pixels[e][s] = clBlue;
            }
         }
      }
      Form1->EditElevation->Text = level;
      Form1->ProgressBar1->Position = level;
      Application->ProcessMessages();
   }
   Form1->ProgressBar1->Position = 0;
   Form1->ProgressBar1->Max = 500;
}

//---------------------------------------------------------------------- RAZE
void raze (void) {
   Form1->ProgressBar1->Max = 1500;
   for (level = 1500; level > 0; level = level - 2) {
      for (int e = 0; e < 492; e++) {
         for (int s = 0; s < 563; s++) {
            if ((sluis[e][s] > level) && sluis[e][s] < level + 3) {
               Form1->Canvas->Pixels[e][s] = clRed;
            }
         }
      }
      Form1->EditElevation->Text = level;
      Form1->ProgressBar1->Position = 1500 - level;
      Application->ProcessMessages();
   }
   Form1->ProgressBar1->Position = 0;
   Form1->ProgressBar1->Max = 500;
}

//--------------------------------------------------------------------- SLICE
void slice (void) {
   render();
   for (int e = 0; e < 492; e++) {
      for (int s = 0; s < 563; s++) {
         if ((sluis[e][s] < level + 50) && (sluis[e][s] > level - 50)) {
            Form1->Canvas->Pixels[e][s] = clYellow;
         }
      }
      Application->ProcessMessages();
   }
}

// ------------------------------------------------------------------- SUN UL
void sunUL (void) {
   gray = true;
   for (int e = 1; e < 491; e++) {
      for (int s = 1; s < 562; s++) {
         topLeft = sluis[e - 1][s - 1];
         bottomRight = sluis[e + 1][s + 1];
         Form1->Canvas->Pixels[e][s] =
            static_cast<TColor>(colorRamp(200, bottomRight - topLeft + 30));
      }
   }
   gray = false;
}

// ------------------------------------------------------------------- SUN UR
void sunUR (void) {
   gray = true;
   for (int e = 1; e < 491; e++) {
      for (int s = 1; s < 562; s++) {
         topRight = sluis[e + 1][s - 1];
         bottomLeft = sluis[e - 1][s + 1];
         Form1->Canvas->Pixels[e][s] =
            static_cast<TColor>(colorRamp(200, bottomLeft - topRight + 30));
      }
   }
   gray = false;
}

//============================================================ EVENT HANDLERS

//---------------------------------------------------------- OPEN FILE BUTTON
void __fastcall TForm1::ButtonOpenFileClick(TObject *Sender)
{
   openFile();   
}

//------------------------------------------------------- CLEAR SCREEN BUTTON
void __fastcall TForm1::ButtonClearClick(TObject *Sender)
{
   Refresh();
}

//------------------------------------------------------- RENDER COLOR BUTTON
void __fastcall TForm1::ButtonRenderColorClick(TObject *Sender)
{
   render();
}

//-------------------------------------------------------- RENDER GRAY BUTTON
void __fastcall TForm1::ButtonRenderGrayClick(TObject *Sender)
{
   gray = true;
   render();
   gray = false;
}

//----------------------------------------------- ELEVATION STATISTICS BUTTON
void __fastcall TForm1::ButtonElevationStatsClick(TObject *Sender)
{
   elevationStatistics();
}

//-------------------------------------------------------------- FLOOD BUTTON
void __fastcall TForm1::ButtonFloodClick(TObject *Sender)
{
   flood();
}

//--------------------------------------------------------------- RAZE BUTTON
void __fastcall TForm1::ButtonRazeClick(TObject *Sender)
{
   raze();
}

//----------------------------------------------------- SUN UPPER LEFT BUTTON
void __fastcall TForm1::ButtonSunULClick(TObject *Sender)
{
   sunUL();
}

//---------------------------------------------------- SUN UPPER RIGHT BUTTON
void __fastcall TForm1::ButtonSunURClick(TObject *Sender)
{
   sunUR();
}

//----------------------------------------------------- SLICE TRACKBAR CHANGE
void __fastcall TForm1::TrackBarSliceChange(TObject *Sender)
{
   level = 1000 - TrackBarSlice->Position;
   Form1->EditElevation->Text = level;
   Application->ProcessMessages();
}

//------------------------------------------------------------- MAX TRACK BAR
void __fastcall TForm1::TrackBarMaxChange(TObject *Sender)
{
   maxElev = TrackBarMax->Position;
   Form1->EditMax->Text = maxElev;
}

//------------------------------------------------------------- MIN TRACK BAR
void __fastcall TForm1::TrackBarMinChange(TObject *Sender)
{
   minElev = TrackBarMin->Position;
   Form1->EditMin->Text = minElev;
}

//------------------------------------------------------------- ON MOUSE MOVE
void __fastcall TForm1::FormMouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
   if (X < 492 && Y < 563) {
      EditElevation->Text = sluis[X][Y];
      lastElev = sluis[X][Y];
   }
}

//---------------------------------------------------- ON PAINTBOX MOUSE DOWN
void __fastcall TForm1::PaintBox1MouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
   gray = true;
   slice();
   gray = false;
}

//---------------------------------------------------------------------------